I had epiliepsy as a child that I grew out of in my teens. That could form a link.
Otherwise, because of the epilepsy, I had no childhood innoculations but got lots of the illnesses instead including mumps, measles, reubella - and my personal freak of medicine acheivement - I had chicken pox 11 (yes that's 11) times in infancy. Could be that all of these have played a role!
I didn't have much junk food as a child so I can't blame childhood diet.
I grew up in a super clean house.
I also took a lot of blows to the head as a child